#include <stdio.h>

/* CHAOS :) */


int main(int argc, char ** argv)
{
  FILE * f = fopen("average.in", "r");
  int i;
  int sects;
  float dist, av, tsec;
  double buf, wuff;
  int team;
  char string[100];
  int hours, min, sec, bla= 0;
  int totmin, totsec=0;

  fscanf(f, "%d %f", &sects, &dist);
bla:  while(fscanf(f, "%d", &team) != EOF)
    {
      tsec=0;
      for(i=0; i<sects;i++)
	{
	  hours=0; min=0; sec=0;
	  if(fscanf(f,"%d:%d:%d", &hours, &min, &sec) > 0)
	    { 

	      tsec = tsec + sec + 60*min + 3600*hours;
	      
	      
	    }
	  else {
	    
	    fscanf(f, "%s\n", string);
	    printf("%3d: -\n", team);
	    goto bla;
	    
	  
	  }
	}

      /*Berechne */
      av = tsec /dist;
      buf = (av/60);
      bla = ((int)av) % 60;
      totmin = (int)buf;
      totsec = bla;
      wuff = av - (totmin*60+totsec);
      if((wuff > 0.5) && (totsec != 59)){
	totsec++;
      }
      if((wuff > 0.5) && (totsec == 59)){
	totsec = 0;
	totmin++;
      }
      if(totsec ==0)
	{
	  printf("%3d: %d:00\n", team, totmin);
	}
      else{
	printf("%3d: %d:%2d\n", team, totmin, totsec);
      }
    
      
	     
	  
	
    }   
  return(0);
}